Propolis accelerates the consolidation phase in distraction osteogenesis.

We evaluated the effect of propolis on new bone formation after distraction osteogenesis (DO). This study examined 3 groups: control group, P100, and P200. Rabbits underwent DO of the left mandible after an osteotomy between the first molar and the mental foramen. Bone mineral content and bone mineral density were evaluated using dual-energy x-ray absorption 1 and 4 weeks after the procedure. The volume of connective tissue and new bone and the number of capillaries were measured using stereologic analysis after the subjects were killed. Dual-energy x-ray absorption showed that the bone mineral content and bone mineral density were higher in the groups treated with propolis by week 4, and these parameters were higher in the P200 group. Stereologic analysis showed no significant differences in connective tissue volume and number of capillaries among the groups. New bone volume was lowest in the P200 group. We concluded that propolis accelerates bone formation and may shorten the consolidation phase with DO.

Cold infarction areas of varying size in the presence of left ventricular dysfunction: the impact on left ventricular ejection fraction determination by gated SPECT compared to radionuclide ventriculography.

The agreement in left ventricular (LV) ejection fraction (EF) determination between the gated perfusion SPECT (GPS) and radionuclide ventriculography (RVG) methods has been reported to show a systematic reduction with increasing EF values. In some reports, this EF difference exceeds 5%, indicating a critical underestimation rate by GPS in terms of clinical reliability. Although the accuracy of endocardial edge detection by means of GPS proves to be reliable, even in patients with large perfusion defects, the accuracy of EF calculation seems to depend on the level of individual EF values. Our objective was to investigate the RVG-GPS agreement in EF determination specifically in patients with myocardial infarction (MI) having perfusion defects including extremely depleted areas and LV dysfunction. Our patients had a EF<50%, a population in which the best agreement values between the above two methods should be found according to the literature. The idea was to test the accuracy of QGS algorithm in the presence of cold perfusion defects and a low probability of EF level influence. Thirty-six patients (26 males; 61.8+/-9.1 y and 10 female; 64.1+/-10.7 y) with MI older than two weeks, having perfusion defects, including all regions of varying size with no visible tracer uptake in rest GPS and RVG-EF<50% were included in the study. Rest-GPS was performed by injecting iv 925 MBq 99mTc-sestamibi (8-time bins) using a dual-headed gamma camera and rest-RVG was performed within the following three days by injecting iv 740 MBq 99mTc-pertechnetate-pyrophosphate (24 time bins). Myocardial perfusion was visually analyzed on a 17 segment-model and summed rest perfusion scores (SRS) were determined. The cold defect number (CDN) was calculated by selecting the myocardial segments with 0%-9% of maximal tracer uptake (grade 4) to identify the extent of the depleted tissue in each patient. The patients with (3)4 adjacent myocardial segments with grade 4 perfusion were considered as having large cold defects (Group 1: GR1). Patients with two or three CDN constituted the Group 2 (GR2; medium cold defects) and those with only one CDN constituted Group 3 (GR3; small cold defects). Hereafter, the relative weight of cold perfusion defects (CD%) and infarcted segments (IS%) were calculated for all patients and subgroups. Of 36 patients studied, 14 patients (39%, GR1) had large cold defects. Eleven patients (30.5%, GR2) had moderate and 11 (30.5%, GR3) had small cold defects. The overall mean value of CDN was 3.03+/-1.96 (1-9). Mean EF values in RVG and GPS among Groups 1, 2 and 3 were 28.78%+/-6.32%, 38.46%+/-6.43%, 38.73%+/-8.55% and 27.0%+/-6.93%, 37.82%+/-8.80%, 33.27%+/-11.65%, respectively. The percentage of patients showing an EF difference pound 5% between RVG and GPS in Groups 1, 2 and 3 were 93%, 73% and 27%, respectively. The CD% and IS% were 19+/-12, 30+/-7, 14+/-3, 6 and 52+/-20, 61+/-18, 50+/-17, 42+/-23 in overall, GR1, GR2 and GR3, respectively. It is concluded that: the negligible underestimation of EF in GR1 by GPS compared to RVG confirms the stability of the geometric modeling algorithm of QGS in this particular patient sub-group. Although the agreement results in patients with smaller defects were probably influenced through the realization of RVG and GPS studies performed on different days, it seems to be rational to set the threshold of RVG-GPS agreement dependency on EF levels in patients with myocardial infarction lower than 50%.

Left ventricular aneurysm in the scope of gated perfusion SPECT: accuracy of detection and ejection fraction calculation.

PURPOSE: The objective of this trial was to investigate the capacity of gated perfusion SPECT (GPS) to detect left ventricular aneurysm (ANV) by comparing QGS and 4D-MSPECT (4DM) algorithms with radionuclide ventriculography (RVG). Secondarily, the comparison of GPS ejection fraction (EF) measurements with those of contrast left ventriculography (LVG) and RVG was aimed. METHODS: Twenty-five patients with ANV confirmed by LVG were studied. The patients underwent RVG and rest Tc-99m-tetrofosmin GPS 1 week after LVG. A 9-segment model was used both in RVG and GPS evaluation. Aneurysm was defined by scoring the wall motion (WM) and phase analysis in RVG; perfusion, wall thickening and WM in GPS. RESULTS: The detection rate of ANV was 96%, 84% and 52% for RVG, QGS and 4DM, respectively. The LVG mean EF (43.52% +/- 16.93%) was significantly higher (P < 0.01) than those of RVG (29.40% +/- 10.90), QGS (30.04% +/- 13.25%) and 4DM (34.92% +/- 13.01%). Moderate to high EF correlation values were obtained between LVG and GPS (r = 0.71-0.79) and GPS-RVG (r = 0.69). There was no significant EF difference between the radionuclide methods except between 4DM-EF and RVG-EF (5.52%, P < 0.05). Wide Bland-Altman limits were observed between the radionuclide methods in EF comparisons (range: 30.5-38.5%). CONCLUSION: GPS seems to have a role in the non-invasive investigation of ANV. QGS-GPS proved to be more reliable (84%) than 4DM-GPS (52%) in the ANV detection. The localization and the extent of the aneurysm itself as well as perfusion and function of adjacent segments may affect aneurysm diagnosis by means of GPS. RVG, QGS-GPS and 4DM-GPS seem not to be interchangeable for routine EF calculation in ANV patients.